Modified polyphenylene ether-polyamide compositions and process

ABSTRACT

Novel modified polyphenylene ether-polyamide compositions comprising polyphenylene ether, polyamide and a polycarboxylic acid and the reaction product thereof and an improved process for preparing the same.

This is a continuation of application Ser. No. 736,490 filed May 20,1985, now abandoned, which is a continuation-in-part of application Ser.No. 612,369 filed May 21, 1984.

The present invention relates to modified polyphenylene ether-polyamidecompositions having improved chemical resistance, processability,elongation properties and/or impact strength as compared to unmodifiedcompositions. More specifically, it relates to a resin composition whichcomprises a combination and/or the reaction product of (a) one or morepolyphenylene ether resins, (b) one or more polyamide resins and (c) atleast one aliphatic polycarboxylic acid or derivative modifier.

The invention also relates to an improved process for the manufacture ofsaid modified polyphenylene ether-polyamide compositions wherein theimprovement comprises precompounding the aliphatic polycarboxylic acidmodifier with either the polyamide or, preferably, the polyphenyleneether prior to compounding with the other polymer. Such precompoundingunexpectedly results in improved physical properties in the finalcomposition over those prepared from the same ingredients withoutprecompounding. Inasmuch as the compositions of the present inventionmay further comprise impact modifiers, reinforcing agents, stabilizersand the like, these may also be precompounded with either of thepolymers for improved properties.

The polyphenylene ether resins are characterized by a unique combinationof chemical, physical and electrical properties over a temperature rangeof more than 600° F., extending from a brittle point of about -275° F.to a heat distortion temperature of about 375° F. This combination ofproperties renders the polyphenylene ethers suitable for a broad rangeof applications. However, in spite of the aforementioned beneficialproperties, the usefulness of the polyphenylene ether resins is limitedas a consequence of their poor processability, impact resistance andchemical resistance.

Finholt (U.S. Pat. No. 3,379,792) discloses polymer blends wherein theprocessability of polyphenylene ether resins may be improved by blendingtherewith from 0.1 to 25% by weight of a polyamide. However, theadvantages of the Finholt invention are limited by the fact that whenthe concentration of the polyamide exceeds 20% by weight, appreciablelosses in other physical properties result. Specifically, there is no,or at best poor, compatibility between the polyphenylene ether and thepolyamide such that phase separation of the resins occurs on molding orthe molded article is inferior in mechanical properties.

Ueno et al. (U.S. Pat. No. 4,315,086) discloses polyphenylene etherblends having improved chemical resistance without a loss of othermechanical properties by blending therewith a polyamide and a specificcompound selected from the group consisting essentially of (A) liquiddiene polymers, (B) epoxy compounds and (C) compounds having in themolecule both of (i) an ethylenic carbon-carbon double bond orcarbon-carbon triple bond and (ii) a carboxylic acid, acid anhydride,acid amide, imide, carboxylic acid ester, amino or hydroxyl group.

Finally, Kasahara et al. (EP46040) discloses the use of a copolymercomprising units of a vinyl aromatic compound and either an alpha,beta-unsaturated dicarboxylic acid anhydride or an imide compoundthereof as a modifier to an impact resistant polyphenyleneether-polyamide blend for improved heat resistance and oil resistance.

Applicants have now discovered novel polyphenylene ether polyamideblends having improved impact strength, elongation, chemical resistance,processability and/or heat resistance as well as reduced waterabsorption as compared to unmodified polyphenylene ether-polyamidecompositions. Specifically, applicants have discovered novel resincompositions having the aforementioned properties comprising acombination of and/or the reaction product of a polyphenylene ether, apolyamide and a property improving amount of (a) an aliphaticpolycarboxylic acid or derivative thereof represented by the formula:

    (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s

wherein R is a linear or branched chain, saturated aliphatic hydrocarbonof from 2 to 20, preferably 2 to 10, carbon atoms; R^(I) is selectedfrom the group consisting of hydrogen or an alkyl, aryl, acyl orcarbonyl dioxy group of 1 to 10, preferably 1 to 4 carbon atoms, mostpreferably hydrogen; each R^(II) is independently selected from thegroup consisting of hydrogen or an alkyl or aryl group of from 1 to 20carbon atoms, preferably from 1 to 10 carbon atoms; each R^(III) andR^(IV) is independently selected from the group consisting essentiallyof hydrogen or an alkyl or aryl group of from 1 to 10, preferably from 1to 6, most preferably 1 to 4, carbon atoms; m is equal to 1 and (n+s) isgreater than or equal to 2, preferably equal to 2 or 3, and n and s areeach greater than or equal to zero and wherein (OR^(I)) is alpha or betato a carbonyl group and at least two carbonyl groups are separated by 2to 6 carbon atoms. Further, these compositions may contain stabilizingand/or property improving amounts of primary or secondary amines.Optionally, the compositions of the present invention may furthercomprise fillers as well as other property enhancing additives such aspolymeric impact modifiers and/or inorganic reinforcing additives and/orother polymers including alkenyl aromatic polymers such as the styrenicpolymers.

Additionally, applicants have now discovered an improved process for thepreparation of the said polyphenylene ether-polyamide blends.Specifically, while most any known process for the preparation of blendcompositions, e.g., melt blending, may be employed in the preparation ofthe compositions of the present invention, applicants have surprisinglyfound further enhancement in impact strength, elongation, processabilityand the like by precompounding the aliphatic polycarboxylic acidmodifier with either of the polyphenylene ether or polyamide resinsprior to compounding with the other. Said precompounding steps may alsobe applied with respect to any additional additives employed in thepreparation of the compositions.

Although the exact physical configuration of the compositions of thepresent invention is not known, it is generally believed that thecompositions comprise a dispersion of one polymer in the other.Applicants believe the likely configuration is wherein the polyphenyleneether is dispersed in a polyamide matrix, however, the inverse may alsobe possible particularly where the polyamide is present in only a minoramount. Applicants also contemplate that there may be present in theproducts produced hereby some graft polyphenylene ether-polyamideproducts. Furthermore, applicants contemplate that grafting, if present,may be such that the polycarboxylic acid may, at least in part, promotegrafting and/or act as a graft-linking agent itself. Thus, all suchdispersions as well as graft, partially grafted and non-grafted productsare within the full intended scope of the invention.

The polyphenylene ethers suitable for use in the practice of the presentinvention are well known in the art and may be prepared by any of anumber of catalytic and non-catalytic processes from correspondingphenols or reactive derivatives thereof. Examples of polyphenyleneethers and methods for their production are disclosed in U.S. Pat. Nos.3,306,874; 3,306,875; 3,257,357; 3,257,358; 3,337,501 and 3,787,361, allincorporated herein by reference. For brevity, the term "polyphenyleneether" as used throughout this specification and the appended claimswill include not only unsubstituted polyphenylene ether (made fromphenol) but also polyphenylene ethers substituted with varioussubstituents. The term also includes polyphenylene ether copolymers,graft copolymers and block copolymers of alkenyl aromatic compounds,especially vinyl aromatic compounds, as disclosed below, and apolyphenylene ether.

Suitable phenol compounds for the preparation of the polyphenyleneethers may be represented by the general formula: ##STR1## wherein eachQ is a monovalent substituent individually selected from the groupconsisting of hydrogen, halogen, aliphatic and aromatic hydrocarbon andhydrocarbonoxy radicals free of a tertiary alpha-carbon atom andhalohydrocarbon and halohydrocarbonoxy radicals free of a tertiaryalpha-carbon atom and having at least two carbon atoms between thehalogen atom and the phenyl nucleus, and wherein at least one Q ishydrogen.

As specific examples of the phenol compound represented by the aboveformula, there may be given phenol; o-, m- and p- cresols; 2,6, 2,5, 2,4and 3,5 dimethylphenols; 2-methyl-6-phenyl-phenol; 2,6-diphenylphenol;2,6-diethylphenol; 2-methyl-6-ethylphenol; and 2,3,5-, 2,3,6- and2,4,6-trimethylphenols. Two or more phenol compounds may be used incombination should copolymers be desired. Additionally, copolyphenyleneethers may also be prepared from a phenol compound of the above generalformula with a phenol compound not represented by the above generalformula including, for example, a dihydric phenol such as bisphenol-A,tetrabromobisphenol-A, resorcinol or hydroquinione.

Illustrative of suitable polyphenylene ethers there may be given, forexample, poly(2,6dimethyl-1,4-phenylene)ether;poly(2-methyl-1,4-phenylene) ether, poly(3-methyl-1,4-phenylene)ether;poly(2,6-diethyl-1,4-phenylene)ether;poly(2-methyl-6-allyl-1,4-phenylene)ether;poly(2,6-dichloromethyl-1,4-phenylene)ether;poly(2,3,6-trimethyl-1,4-phenylene) ether; poly(2,3,5,6-tetramethylphenylene)ether; poly(2,6-dichloro-1,4-phenylene)ether;poly(2,6-diphenyl-1,4-phenylene)ether;poly(2,5-dimethyl-1,4-phenylene)ether and the like. Further, asmentioned above, copolymers of the phenol compounds may also be used.

Preferred polyphenylene ethers will have the formula: ##STR2## where Qis as defined above and n is at least 50, preferably from about 50 toabout 200. Examples of polyphenylene ethers corresponding to the aboveformula can be found in the above referenced patents and include, amongothers: poly(2,6-dilauryl-1,4-phenylene)ether;poly(2,6-diphenyl-1,4-phenylene)ether;poly(2,6-dimethyloxy-1,4-phenylene)ether;poly(2,6-diethoxy-1,4-phenylene)ether;poly(2-methoxy-6-ethyoxy-phenylene)ether;poly(2-ethyl-6-stearyloxy-1,4-phenylene)ether;poly(2,6-dichloro-1,4-phenylene)ether;poly(2-methyl-6-phenyl-1,4-phenylene)etherpoly(2,6-dibenzyl-1,4-phenylene)ether;poly(2-ethoxy-1,4-phenylene)ether; poly(2-chloro-1,4-phenylene)ether;poly(2,6-dibromo-1,4-phenylene) ether; and the like.

For the purpose of the present invention, an especially preferred familyof polyphenylene ethers include those having a C₁ to C₄ alkylsubstitution in the two positions ortho to the oxygen ether atom.Illustrative members of this class are:poly(2,6-dimethyl-1,4-phenylene)ether;poly(2,6-diethyl-1,4-phenylene)ether;poly(2-methyl-6-ethyl-1,4-phenylene)ether;poly(2,6-dipropyl-1,4-phenylene)ether;poly(2-ethyl-6-propyl-1,4-phenylene)ether; and the like; most preferablypoly(2,6-dimethyl-1,4-phenylene)ether.

One method for the production of the above polyphenylene ethers is bythe oxidation of a phenol compound by oxgen or an oxygen-containing gasin the presence of a catalyst for oxidative coupling. There is noparticular limitation as to the choice of catalysts and any catalystsfor oxidation polymerization can be employed. As typical examples of thecatalyst, there may be given a catalyst comprising a cuprous salt and atertiary amine and/or secondary amine, such as cuprouschloride-trimethylamine and dibutylamine, cuprous acetate-triethylamineor cuprous chloride-pyridine; a catalyst comprising a curpic salt, atertiary amine, and an alkali metal hydroxide, such as cupricchloride-pyridine-potassium hydroxide; a catalyst comprising a manganesesalt and a primary amine, such as manganese chloride-ethanolamine ormanganese acetate-ethylenediamine; a catalyst comprising a manganesesalt and an alcoholate or phenolate, such as manganese chloride-sodiummethylate or manganese chloride-sodium phenolate; and a catalystcomprising a cobalt salt and a tertiary amine.

Polyamides suitable for the preparation of the compositions of thepresent invention may be obtained by polymerizing amonoamino-monocarboxylic acid or a lactam thereof having at least 2carbon atoms between the amino and carboxylic acid group; or bypolymerizing substantially equimolar proportions of a diamine whichcontains at least 2 carbon atoms between the amino groups and adicarboxylic acid; or by polymerizing a monoaminocarboxylic acid or alactam thereof as defined above together with substantiallyequimolecular proportions of a diamine and a dicarboxylic acid. Thedicarboxylic acid may be used in the form of a functional derivativethereof, for example an ester or acid chloride.

The term "substantially equimolecular" proportions (of the diamine andof the dicarboxylic acid) is used to cover both strict equimolecularproportions and slight departures therefrom which are involved inconventional techniques for stabilizing the viscosity of the resultantpolyamides.

Examples of the aforementioned monoamino-monocarboxylic acids or lactamsthereof which are useful in preparing the polyamides include thosecompounds containing from 2 to 16 carbon atoms between the amino andcarboxylic acid groups, said carbon atoms forming a ring with the--CO--NH-- group in the case of a lactam. As particular examples ofaminocarboxylic acids and lactams there may be mentioned -aminocaproicacid, butyrolactam, pivalolactam, caprolactam, capryl-lactam,enantholactam, undecanolactam, dodecanolactam and 3-and 4- aminobenzoicacids.

Diamine suitable for use in the preparation of the polyamides includethe straight chain and branched, alkyl, aryl and alkyl-aryl diamines.Such diamines include, for example, those represented by the generalformula:

    H.sub.2 N(CH.sub.2).sub.n NH.sub.2

wherein n is an integer of from 2 to 16, such as trimethylenediamine,tetramethylenediamine, pentamethylenediamine, octamethylenediamine andespecially hexamethylenediamine, as well as trimethyl hexamethylenediamine, meta-phenylene diamine, meta-xlylene diamine and the like.

The dicarboxylic acids may be aromatic, for example isophthalic andterephthalic acids. Preferred dicarboxylic acids are of the formula

    HOOC--Y--COOH

wherein Y represents a divalent aliphatic group containing at least 2carbon atoms, and examples of such acids are sebacic acid,octadecanedoic acid, suberic acid, glutaric acid, pimelic acid andadipic acid.

Typical examples of the polyamides or nylons, as these are often called,include for example polyamides 6, 6/6, 11, 12, 6/3, 6/4, 6/10 and 6/12as well as polyamides resulting from terephthalic acid and/orisophthalic acid and trimethyl hexamethylene diamine, polyamidesresulting from adipic acid and meta xylylenediamines, polyamidesresulting from adipic acid, azelaic acid and2,2-bis-(p-aminocyclohexyl)propane and polyamides resulting fromterephthalic acid and 4,4'-diamino-dicyclohexylmethane. Mixtures and/orcopolymers of two or more of the foregoing polyamides or prepolymersthereof, respectively, are also within the scope of the presentinvention. Preferred polyamides are the polyamides 6, 6/6, 11 and 12,most preferably polyamide 6/6.

It is also to be understood that the use of the term "polyamides" hereinand in the appended claims is intended to include the toughened or supertough polyamides. Super tough polyamides, or super tough nylons, as theyare more commonly known, are available commercially, e.g. from E. I.duPont under the tradename Zytel ST, or may be prepared in accordancewith a number of U.S. Pat. Nos. including, among others, Epstein U.S.Pat. No. 4,174,358; Novak U.S. Pat. No. 4,474,927; Roura U.S. Pat. No.4,346,194; and Joffrion U.S. Pat. No. 4,251,644, herein incorporated byreference. These super tough nylons are prepared by blending one or morepolyamides with one or more polymeric or copolymeric elastomerictoughening agents. Suitable toughening agents are disclosed in theabove-identified U.S. Pat. Nos. as well as in Caywood, Jr. U.S. Pat. No.3,884,882 and Swiger U.S. Pat. No. 4,147,740 and Gallucci et al.,"Preparation and Reactions of Epoxy-Modified Polyethylene", J. APPL.POLY. SCI., V. 27, pp. 425-437 (1982) herein incorporated by reference.Typically, these elastomeric polymers and copolymers may be straightchain or branched as well as graft polymers and copolymers, includingcore-shell graft copolymers, and are characterized as havingincorporated therein either by copolymerization or by grafting on thepreformed polymer, a monomer having functional and/or active or highlypolar groupings capable of interacting with or adhering to the polyamidematrix so as to enhance the toughness of the polyamide polymer.

The blending ratio of polyphenylene ether to polyamide is 5 to 95% bywt. preferably 30 to 70% by wt. of the former to 95 to 5% by wt.,preferably 70 to 30% by wt. of the latter. When the polyamide is lessthan 5 wt. percent, its effect to improve solvent resistance is small,while when it exceeds 95 wt. percent, thermal properties such as heatdistortion temperature tend to become poor.

Compounds useful for improving the physical properties of thepolyphenylene ether-polyamide compositions are aliphatic polycarboxylicacids and derivatives thereof represented by the formula:

    (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s

wherein R is a linear or branched chain, saturated aliphatic hydrocarbonof from 2 to 20, preferably 2 to 10, carbon atoms; R^(I) is selectedfrom the group consisting of hydrogen or an alkyl, aryl, acyl orcarbonyl dioxy group of 1 to 10, preferably 1 to 6, most preferably 1 to4, carbon atoms, especially preferred is hydrogen; each R^(II) isindependently selected from the group consisting of hydrogen or an alkylor aryl group of from 1 to 20 carbon atoms, preferably from 1 to 10carbon atoms; each R^(III) and R^(IV) is independently selected from thegroup consisting essentially of hydrogen or an alkyl or aryl group offrom 1 to 10, preferably from 1 to 6, most preferably 1 to 4, carbonatoms; m is equal to 1 and (n+s) is greater than or equal to 2,preferably equal to 2 or 3, and n and s are each greater than or equalto zero and wherein (OR^(I)) is alpha or beta to a carbonyl group and atleast two carbonyl groups are separated by 2 to 6 carbon atoms.Obviously, R^(I), R^(II), R^(III) and R^(IV) cannot be aryl when therespective substituent has less than 6 carbon atoms.

In general the polycarboxylic acid modifiers suitable for use hereinencompass three classes, the polycarboxylic acids, the acid esters andthe acid amides. Thus, when used herein and in the appended claims, itis to be understood that the term "polycarboxylic acid" refers to allthese classes. Illustrative of suitable polycarboxylic acids there maybe given citric acid, malic acid, and agaricic acid; including thevarious commercial forms thereof, such as, for example, the anhydrousand hydrated acids. Illustrative of acid esters useful herein includefor example, acetyl citrate and mono- and/or di- stearyl citrates andthe like. Suitable acid amides useful herein include for exampleN,N'-diethyl citric acid amide; N,N'-dipropyl citric acid amide;N-phenyl citric acid amide; N-dodecyl citric acid amide; N,N'-didodecylcitric acid amide and N-dodecyl malic acid amide. Derivatives of theforegoing polycarboxylic acids are also suitable for use in the practiceof the present invention. Especially preferred derivatives are the saltsthereof, including the salts with amines and/ preferably, the alkali andalkaline metal salts. Exemplary of suitable salts include calciummalate, calcium citrate, potassium malate and potassium citrate.

The amount of the polycarboxylic acid to be used is that amount whichmanifests property improvement, especially improved compatibility aswell as improved processability, impact strength and/or elongation, inthe polyphenylene ether-polyamide compositions. In general, the amountof polycarboxylic acid compounds used will be up to about 4%, preferablyfrom about 0.05 to about 4%, most preferably from about 0.1 to about 2%by weight based on the total composition. Although higher amounts may beused, the preparation of such compositions causes significant problemsin processing resulting in compositions having large die-swell and/ormay not give optimum property improvement. The specific amount of thepolycarboxylic acid compound to be used to achieve optimum results for agiven composition is dependent, in part, on the specific polycarboxylicacid and polymers used, the weight ratio of said polymers and theprocessing conditions.

In addition to the improved processability impact strength andelongation, many of the compositions prepared in accordance with thepresent invention manifest improvements in other physical properties andcharacteristics including for example, reduced water absorption.

The above-mentioned property improving polycarboxylic acid compound maybe used alone or in combination with a primary or secondary amine. Thepresence of the amine is found to enhance the improvement of certainphysical properties, especially brightness, when used in combinationwith various polycarboxylic acids, especially for example with malicacid. Suitable amines include those primary and secondary amines havingfrom 1 to about 20, preferably from 1 to about 10 carbon atoms.Illustrative of said suitable amines there may be given, methylethylamine, diethylamine, butylamine, dibutylamine, analine,n-octadecylamine and the like. The amount of the primary or secondaryamine to be used is generally up to about 3% by wt., preferably fromabout 0.35 to about 1% by wt.

In the practice of the present invention, it may be further desirable toadd an additional modifier resin or resin combination to further improvethe physical properties, particularly the impact strength, and/orprocessability of the composition. Such modifier resins are well knownin the art and are typically derived from one or more monomers selectedfrom the group consisting of olefins, vinyl aromatic monomers, acrylicor alkyl acrylic acids and their ester derivatives as well as conjugateddienes. Especially preferred modifier resins are the rubberyhigh-molecular weight materials including natural and syntheticpolymeric materials showing elasticity at room temperature. Suitablemodifier resins include both homopolymers and copolymers, includingrandom, block, radial block, graft and core-shell copolymers as well ascombinations thereof.

Polyolefins or olefin-based copolymer employable in the practice of thepresent invention include, among others, low density polyethylene, highdensity polyethylene, linear low density polyethylene, isotacticpolypropylene, poly(1-butene), poly(4-methyl-1-pentene),propylene-ethylene copolymers, and the like. Additional olefincopolymers include copolymers of one or more alpha olefins, particularlyethylene, with copolymerizeable monomers including for example vinylacetate, acrylic acids and alkyl acrylic acids as well as the esterderivatives thereof including for example, ethylene acrylic acid,ethylacrylate, methacrylic acid, methyl methacrylate and the like.Finally, an additional class of olefin-based copolymers suitable for useherein include the ionomer resins, which may be wholly or partiallyneutralized with metal ions.

A second class of modifier resins employable herein are those derivedfrom the vinyl aromatic monomers. These include, for example, modifiedand unmodified polystyrenes, ABS type graft copolymers; AB and ABA typeblock and radial block copolymers and vinyl aromatic conjugated dienecore-shell graft copolymers. Modified and unmodified polystyrenesinclude homopolystyrenes and rubber modified polystyrenes, such asbutadiene rubber modified polystyrene otherwise referred to as highimpact polystyrene or HIPS. Additional useful polystyrenes includecopolymers of styrene and various monomers, including for example,poly(styrene-acrylonitrile) (SAN), styrene-butadiene copolymers as wellas the modified alpha and para substituted styrenes and any of thestyrene resins disclosed in U.S. Pat. No. 3,383,435, herein incorporatedby reference. ABS type of graft copolymers are typified as comprising arubbery polymeric backbone derived from a conjugated diene alone or incombination with a monomer copolymerizable therewith having graftedthereon at least one monomer, and preferably two, selected from thegroup consisting of monoalkenyl arene monomers and substitutedderivatives thereof as well as acrylic monomers such as acrylonitrilesand acrylic and alkyl acrylic acids and their esters.

An especially preferred class of vinyl aromatic monomer derived polymerresins are the block copolymers comprising monoalkenyl arene blocks andhydrogenated, partially hydrogenated and non-hydrogenated conjugateddiene blocks and represented as AB and ABA block copolymers. Suitable ABtype block copolymers are disclosed in for example U.S. Pat. Nos.3,078,254; 3,402,159; 3,297,793; 3,265,765; and 3,594,452 and UK PatentNo. 1,264,741, all herein incorporated by reference. Exemplary oftypical species of AB block copolymers there may be given:

polystyrene-polybutadiene (SBR)

polystyrene-polyisoprene and

poly(alpha-methylstyrene)-polybutadiene.

Such AB block copolymers are available commercially from a number ofsources including Phillips under the trademark Solprene.

Additionally, ABA triblock copolymers and processes for their productionas well as hydrogenation, if desired, are disclosed in U.S. Pat. Nos.3,149,182; 3,231,635; 3,462,162; 3,287,333; 3,595,942; 3,694,523 and3,842,029, all incorporated herein by reference.

Exemplary of typical species of triblock copolymers there may be given:

polystyrene-polybutadiene-polystyrene (SBS)

polystyrene-polyisoprene-polystyrene (SIS)

poly(alpha-methylstyrene)-polybutadiene-poly(alpha-methylstyrene) and

poly(alpha-methylstyrene)-polyisoprene-poly(alpha-methystyrene).

A particularly preferred class of such triblock copolymers are availablecommercially as CARIFLEX®, KRATON D® and KRATON G® from Shell.

A third class of modifier resins suitable for use in the instantinvention are those derived from conjugated dienes. While manycopolymers containing conjugated dienes have been discussed above,additional conjugated diene modifier resins include for examplehomopolymers and copolymers of one or more conjugated dienes includingfor example polybutadiene, butadiene-styrene copolymers,isoprene-isobutylene copolymers, chlorobutadiene polymers,butadiene-acrylonitrile copolymers, polyisoprene, and the like. Finally,ethylene-propylene-diene monomer rubbers are also intended to be withinthe full scope of the present invention. These EPDMs are typified ascomprising prodominately ethylene units, a moderate amount of propyleneunits and only a minor amount, up to about 20mole % of diene monomerunits. Many such EPDM's and processes for the production thereof aredisclosed in U.S. Pat. Nos. 2,933,480; 3,000,866; 3,407,158; 3,093,621and 3,379,701, herein incorporated by reference.

An additional group of modifier resins employable in the instantinvention are the core-shell type graft copolymers. In general, theseare characterized as having a predominately conjugated diene rubberycore or a predominately cross-linked acrylate rubbery core and one ormore shells polymerized thereon and derived from monoalkenyl areneand/or acrylic monomers alone or, preferably, in combination with othervinyl monomers. Such core-shell copolymers are widely availablecommercially, for example, from Rohm and Haas Company under thetradenames KM-611, KM-653 and KM-330, and are described in U.S. Pat.Nos. 3,808,180; 4,034,013; 4,096,202; 4,180,494 and 4,292,233.

Also within the scope of the present invention are the core-shellcopolymers wherein an interpenetrating network of the resins employedcharacterizes the interface between the core and shell. Especiallypreferred in this regard are the ASA type copolymers available fromGeneral Electric Company and sold as GELOY™ resin and described in U.S.Pat. No. 3,944,631.

It is also to be understood that in addition to the straight polymersand copolymers described above, there may be employed such polymers andcopolymers having copolymerized therewith or grafted thereon monomershaving functional groups and/or polar or active groups. Suchfunctionalized or activated polymers and copolymers are described in theabove-mentioned Epstein, Novak, Roura, Joffrion, Caywood, Swiger andGallucci references cited above with respect to the discussion ontoughened polyamides. All of such functionalized or activated polymersand copolymers may be directly blended with the ingredients to thepresent compositions or, as described above, may be precompounded with apolyamide or polyphenylene ether. Finally, other suitable modifierresins and high molecular weight rubbery materials which may be employedin the practice of the present invention include for example thiokolrubber, polysulfide rubber, polyurethane rubber, polyether rubber (e.g.polypropylene oxide), epichlorhydric rubber, ethylene propylene rubber,thermoplastic polyester elastomers, thermoplastic ether-ester elastomersand the like.

The amount of the rubbery polymer used will be up to about 100 parts byweight, preferably from about 5 to about 50 parts by weight based on 100parts by weight of a mixture of polyphenylene ether and polyamide.However, when the amount is less than 2 parts by weight, the effect ofthe rubbery polymer to improve impact resistance is poor. When theamount is more than 100 parts by weight, the impact resistance is muchimproved, however, some loss of other physical properties may result.Thus, in the interest of balancing impact resistance and other physicalproperties, it is preferred to use less than 100 parts by weight of therubbery polymer. It is also to be understood that combinations of theabove-mentioned modifier resins may be employed and are within the fullintended scope of the present invention.

Finally, in addition to the foregoing, the polyphenylene ether-polyamideresin compositions of the present invention may further comprise otherreinforcing additives, including glass fibers, carbon fibers, mineralfillers and the like as well as various flame retardants, colorants,stabilizers and the like known to those skilled in the art.

When employed in the practice of the present invention, reinforcingadditives should be used in an amount up to no more than about 50 wt. %based on the total composition, preferably no more than about 30 wt. %.Especially preferred reinforcing additives are the filamentous andchopped glass fibers. Such glass fibers may be untreated or, preferably,treated with a silane or titanate coupling agent, and are well known inthe art and widely available from a number of manufacturers.

Suitable stabilizers for use in the practice of the present inventiongenerally include most any of the known thermal and oxidativestabilizers suitable for use with either polyamides or polyphenyleneethers. Especially preferred are those stabilizers suitable for use withpolyamides. For example, liquid phosphates and hindered phenols may beemployed as well as stabilizer packages encompassing combinations ofhindered phenols and potassium and cuprous salts.

The method for producing the resin compositions of the present inventionis not particularly limited, and the conventional methods aresatisfactorily employed. Generally, however, melt blending methods aredesirable. The time and temperature required for melt-blending are notparticularly limited, and they can properly be determined according tothe composition of the material. The temperature varies somewhat withthe blending ratio of the polyphenylene ether to polyamide, but it isgenerally within a range of 270° to 350° C. A prolonged time and/or ahigh shear rate is desirable for mixing, but the deterioration of theresin composition advances. Consequently, the time needs to bedetermined taking into account these points.

Any of the melt-blending methods may be used, if it can handle a moltenviscous mass. The method may be applied in either a batchwise form or acontinuous form. Specifically, extruders, Bambury mixers, rollers,kneaders and the like may be exemplified.

While all ingredients may be initially and directly added to theprocessing system, applicants have surprisingly found that the physicalproperties of the composition, particularly impact strength andelongation, are greatly enhanced by initially precompounding one of thepolymer resins, preferably the polyphenylene ether, with thepolycarboxylic acid prior to blending with the other polymer. Suchprecompounding may be done in two steps wherein the polycarboxylic acidand the polyphenylene ether are melt extruded to form pellets which arethen blended through extrusion with the polyamide or one can employ anextrusion apparatus or melt blending apparatus wherein the polyphenyleneether and polycarboxylic acid are fed at the throat of the screw and thepolyamide is subsequently added to the extrusion system in a downstreamfeed port. In this latter method, the polycarboxylic acid andpolyphenylene ether are melt blended and in a molten state when thepolyamide is added.

With respect to the other ingredients of the compositions, allingredients may be directly added to the processing system or certainadditives may be precompounded with each other or either polymer productblending with the other polymer. For example, as discussed above, impactmodifier or toughening agents may be precompounded with a polyamide toform a super tough polyamide. Alternatively, the polyphenylene ether maybe precompounded with the rubber polymer or other additional resin andthe polycarboxylic acid and subsequently compounded with the polyamide.Furthermore, the amine compound, if used, may be premixed and/or reactedwith a polycarboxylic acid and precompounded with a polyphenylene etherprior to compounding with a polyamide. In essence, any system ofprecompounding may be employed in the practice of the present invention;however, the tremendous and unexpected improvement and physicalproperties is most apparent when at a minimum the polycarboxylic acid isprecompounded with the polyphenylene ether. While the polycarboxylicacid may be precompounded with a polyamide, the enhancement and physicalproperties is not as great.

The following examples are presented in order that those skilled in theart may better understand how to practice the present invention. Theseexamples are merely presented by way of illustration and are notintended to limit the invention thereto. Unless otherwise stated, allformulations are expressed in terms of parts by weight.

EXAMPLES 1 and 2

A series of polyphenylene ether-polyamide compositions within andoutside of the scope of the present invention were prepared. Allcompositions were prepared on a single screw extruder by direct additionof ingredients and extruded at 300° C. The specific composition and thephysical properties thereof are shown in Table 1

                  TABLE 1                                                         ______________________________________                                        Example           A         1      2                                          ______________________________________                                        polyphenylene ether.sup.a                                                                       70        70     70                                         polyamide 6,6.sup.b                                                                             30        30     30                                         citric acid (anhydrous)                                                                         --        1.0    --                                         malic acid        --        --     1.0                                        Unnotched Izod (ft.-lbs./in.)                                                                   2.8       16.7   8.5                                        ______________________________________                                         .sup.a poly(2,6dimethyl-1,4-phenylene)ether produced by General Electric      Company                                                                       .sup.b polyamide 6,6 from duPont                                         

As seen from example 1 and 2 and comparative example A, the addition ofthe polycarboxylic acid to the polyphenylene ether-polyamide compositiongreatly improved the physical properties of such blends as demonstratedby the higher impact strength. Additionally, the compositions were foundto have good compatibility as parts molded from these compositions weredevoid of streaks and or delamination which are often associated withincompatibility. The compositions within the scope of the invention werealso found to have improved elongation, processability and chemicalresistance.

EXAMPLES 3-6

A second series of examples were prepared demonstrating theapplicability of the present invention to rubber modified polyphenyleneether-polyamide blends. These examples were prepared on a twin screwextruder at about 575° F. The specific compositions of these examples aswell as the physical properties thereof were as shown in Table 2.

                  TABLE 2                                                         ______________________________________                                                     B    3       4       5    6                                      ______________________________________                                        polyphenylene ether.sup.a                                                                    49     49      49    49   49                                   polyamide 6,6.sup.b                                                                          41     41      41    41   41                                   citric acid (anhydrous)                                                                      --     0.1     0.25  0.5  --                                   malic acid     --     --      --    --   0.25                                 SEBS.sup.c     10     10      10    10   10                                   Gardner Impact (in.-lbs.)                                                                    18     >320    >320  184  >320                                 Notched Izod (ft.-lb./in.)                                                                   0.8    3.0     2.6   1.5  2.4                                  % Tensile elongation                                                                         8      25      33    15   31                                   ______________________________________                                         .sup.a poly(2,6dimethyl-1,4-phenylene)ether from General Electric Company     .sup.b polyamide 6,6 from duPont                                              .sup.c Styrene hydrogenated polybutadiene styrene triblock copolymer from     Shell                                                                    

The results shown in Table 2 clearly demonstrate the benefit andeffectiveness of the polycarboxylic acid in the rubber modifiedpolyphenylene ether-polyamide blends. Additionally, parts prepared fromthe composition within the scope of the present invention were free ofstreaks and/or delamination.

EXAMPLE 7

Two blends of 70% by wt. polyphenylene ether and 30% polyamide 6 wereprepared, one with 0.5 phr citric acid and the other without anypolycarboxylic acid modifier/compatibilizer. The unnotched izod impactstrengths of the latter was only 2.6 ft.-lbs./in. whereas the unnotchedizod impact strength of the composition according to the inventionincreased to 3.2 ft.-lbs./in. This composition also demonstratedimprovement of other physical properties including for example tensileelongation.

EXAMPLES 8-10

A series of polyphenylene ether-polyamide compositions within andoutside of the scope of the present invention were prepared. Allcompositions were prepared on a twin screw extruder by direct additionof ingredients and extruded at approximately 285° C. under vacuum at ascrew speed of 250 rpm. The specific compositions the physicalproperties thereof are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                         Example        C       8       9      10                                     ______________________________________                                        polyphenylene ether.sup.a                                                                     50      50      50     50                                     polyamide 6,6.sup.b                                                                           --      --      50     --                                     polyamide 6,6.sup.c                                                                           50      50      --     --                                     polyamide 6,6.sup.d                                                                           --      --      --     50                                     citric acid (anhydrous) 1       1      1                                      Notched Izod (ft.lb./in.)                                                                     .5      1.0     1.1    1.0                                    Unnotched Izod (ft.lb./in.)                                                                   10*     >11.7   >11.7  >11.7                                  Tensile Yield Strength                                                                        10.8    11.0    11.2   11.0                                   (psi) × 10.sup.3                                                        Tensile Elongation (%)                                                                        7       24      31.5   21                                     ______________________________________                                         .sup.a polyphenylene ether from General Electric Company                      .sup.b&c Fabenyl 45 APBH and R600, respectively from Tubize Polymers SA,      Belgium.                                                                      .sup.d polyamide 6,6 from du Pont                                             *one out of six bars shows a value >11.7                                 

These examples demonstrate the improved physical properties associatedwith the use of citric acid in polyphenylene ether-polyamide blends.Specifically, these compositions demonstrated improved compatibility,notched and unnotched izod impact strength, tensile yield strength andelongation as compared to the unmodified composition.

EXAMPLES 11-17

Several compositions were prepared on a twin screw extruder at 285° C.with a screw speed of 300 rpm above. These compositions furtherdemonstrate the applicability of the invention to rubber modified aswell as stabilized and pigmented compositions, at various levels of thepolycarboxylic acid additive. The compositions and properties thereofare shown in Table 4. All amounts are in parts by weight.

Once again these examples demonstrate the excellent properties obtainedby the compositions of the present invention. As seen in examples 13 and14, the loss of impact strength by incorporating the stabilizer additivecan be overcome by increasing the amount of polycarboxylic acid. Thesame is also true for compositions incorporating therein TiO₂ pigment.In general, these compositions had improved physical properties as wellas compatibility as evidenced by the lack of streaks and/or delaminationin molded parts.

                                      TABLE 4                                     __________________________________________________________________________    Example      D 11  12   13  14  15  16  17                                    __________________________________________________________________________    polyphenylene ether.sup.a                                                                  45                                                                              45  45   45  45  45  45  45                                    polyamide 6,6.sup.b                                                                        45                                                                              45  45   45  45  45  45  45                                    citric acid-1-hydrate                                                                        0.35                                                                              0.7  0.35                                                                              0.7 0.35                                                                              0.7 0.35                                  phosphite stabilizer    1   1           1                                     TiO.sub.2                   5   5   5                                         SBS.sup.c    10                                                                              10  10   10  10  10  10  10                                    Unnotched Izod (ft.lb./in.)                                                                  5.3(4)                                                                            6.0(5)                                                                             2.4(0)                                                                            4.3(3)                                                                            3.6(0)                                                                            4.7(2)                                                                            1.9(0)                                Falling Dart Impact                                                                        14                                                                              162(4)                                                                            >162(4)                                                                            49(0)                                                                             146(2)                                                                            84(0)                                                                             213(2)                                                                            30(0)                                 (ft.lb.)                                                                      Tensile Yield                                                                              7.5                                                                             8.4 8.5  8.7 8.4 8.5 8.6 8.5                                   Strength (psi × 10.sup.3)                                               Tensile Elongation (%)                                                                     9.2                                                                             49.7                                                                              57.1 17.3                                                                              45.9                                                                              30.1                                                                              40.7                                                                              12.2                                  __________________________________________________________________________     .sup.a poly(2,6 dimethyl1,4-phenylene)ether from General Electric Company     .sup.b Fabenyl 45 APBH, water content 0.3-0.4.                                .sup.c styrenebutadiene-styrene triblock copolymer, Cariflex/KRATON D fro     Shell                                                                         *Numbers in parenthesis represent the number of test parts out of five        tested that did not break at 162 ft.lbs.                                 

EXAMPLES 18-21

Compositions in accordance with the present invention were prepared on atwin screw extruder at 295° C. and screw speed 250 rpm. Thesecompositions further comprised an amine compound with and without aphosphite stabilizer. The compositions and the properties thereof areshown in Table 5.

As these examples demonstrate, excellent physical properties areattained by these compositions.

                                      TABLE 5                                     __________________________________________________________________________    Example           E  18  19  20  21                                           __________________________________________________________________________    polyphenylene ether.sup.a                                                                       50 50  50  50  50                                           polyamide 6,6.sup.b                                                                             50 50  50  50  50                                           citric acid-1-hydrate                                                                              0.7 0.7 0.7 0.7                                          phosphite stabilizer --  0.35                                                                              --  --                                           dibutylamine         --  0.35                                                                              0.35                                                                              0.7                                          Notched Izod ft.lb/in.                                                                          0.69                                                                             1.23                                                                              1.0 1.2 1.0                                          Unnotched Izod ft.lb./in.*                                                                         11.7(3)                                                                           9.7(0)                                                                            7.0(1)                                                                            11.6(0)                                      Tensile Yield strength (× 10.sup.3 psi)                                                   7.8                                                                              10.9                                                                              10.2                                                                              10.8                                                                              10.1                                         Elongation %      5.5                                                                              19.7                                                                              10.7                                                                              14.7                                                                              20.8                                         __________________________________________________________________________     .sup.a polyphenylene ether from General Electric Company                      .sup.b Fabenyl 45APBH from Tubize Polymers S.A. Belgium.                      *Number in parenthesis represents the number of nonbroken bars out of six     tested that did not break at 11.7 ft.lbs.                                

EXAMPLE 22

Two examples of polyphenylene ether-polyamide compositions within andoutside the scope of the present invention were prepared on a twin screwextruder at 285° C. and screw speed of 200 rpm. The specificcompositions and physical properties thereof are shown in Table 6.

These examples further demonstrate the applicability of the presentinvention to other polycarboxylic acids, specifically malic acid.

                  TABLE 6                                                         ______________________________________                                        Example                F      22                                              ______________________________________                                        polyphenylene ether.sup.a                                                                            50     50                                              polyamide 6,6.sup.b    50     50                                              malic acid                    1                                               Notched Izod ft.lb/in. .69    .71                                             Tensile Yield Strength × 10.sup.3 psi                                                          7.8    8.2                                             Tensile Elongation (%) 5.5    6.5                                             ______________________________________                                         .sup.a&b see footnotes Table 3.                                          

EXAMPLES 23-25

Several additional examples were prepared demonstrating various otherpolycarboxylic acid modifiers employable in the practice of the instantinvention. The mono-stearyl citrate employed is from Pfiezer Chemicalsand actually comprises a 22/78 mixture of the mono- and di- stearylesters of citric acid. Acetyl citric acid was prepared inhouse byallowing acetyl chloride to react with the hydroxy group of the citricacid. The carboxylic acid salt, calcium malate, was obtained fromPfaltz-Bauer. The results obtained with these polycarboxylic acids andderivatives were as shown in Table 7.

                  TABLE 7                                                         ______________________________________                                        Example         G      23       24   25                                       ______________________________________                                        polyphenylene ether.sup.a                                                                     70     70       70   70                                       polyamide 6,6.sup.b                                                                           30     30       30   30                                       Monostearyl citrate                                                                           --     1.12     --   --                                       Acetyl citric acid                                                                            --     --       0.5  --                                       Calcium Malate  --     --       --   0.5                                      Unnotched Izod  2.8    4.1      6.9  6.9                                      ft.lb/in.                                                                     ______________________________________                                         .sup.a&b see footnotes Table 3.                                          

EXAMPLES 26-32

An additional series of examples were prepared, this time demonstratingthe utility of various acid-amides, in the present invention. Theacid-amides were prepared by dissolving the respect acid intetrahydrofuran (THF) and then adding in a drop wise fashion the aminewhile constantly stirring. Depending upon the amine employed, the formedacid-amides precipitated out or formed a highly viscous solution. In theformer case, the precipitate was filtered, washed with clear THF anddried in a vacuum-oven. In the latter case, THF was removed byrotary-evaporation and the remaining paste dried in a vacuum-oven andthe product crystallized. The specific reactants and ratios thereofemployed and the products obtained were as shown in Table 8.

These acid-amides were then used, on an equimolar basis, except in thecase of the malic acid based examples, in accordance with the presentinvention to demonstrate their effectiveness as property enhancers. Thecompositions and the properties obtained were as shown in Tables 9 and10. From Tables 9 and 10 it is apparent that acid-amides derived fromamines having 6 or less carbon atoms are preferred. While acid-amidesprepared from amines having more than 6 carbon atoms appear to havelittle or no effect on physical properties, some improvement in thecolor of the resultant resin was noticed.

                                      TABLE 8                                     __________________________________________________________________________                                        Precipitate                                                 Ratio of          formation                                 Amine  Polycarboxylic acid                                                                      Amine/Acid                                                                           Reaction Product                                                                         (A/B).sup.c                               __________________________________________________________________________    Diethylamine                                                                         citric acid-1-hydrate                                                                    1:1    N,N'--diethyl citric                                                                     A                                                                  acid amide                                           propylamine                                                                          citric acid-1-hydrate                                                                    2:1    N,N'--dipropyl citric                                                                    A                                                                  acid amide                                           aniline.sup.a                                                                        citric acid-1-hydrate                                                                    1:1    N--phenyl citric acid                                                                    B                                                                  amide                                                dodecylamine                                                                         citric acid-1-hydrate                                                                    1:1    N--dodecyl citric acid                                                                   B                                                                  amide                                                dodecylamine                                                                         citric acid-1-hydrate.sup.b                                                              2:1    N,N'--didodecyl citric                                                                   B                                                                  acid amide                                           dodecylamine                                                                         d,1-malic acid.sup.b                                                                     1:1    N--dodecyl malic acid                                                                    B                                                                  amide                                                __________________________________________________________________________     .sup.a Purified by vacuum distillation (Fisher Spalt Rohr system).            .sup.b Citric acid/malic acid dissolved at T = 55° C.; reaction        also carried out at this temperature                                          .sup.c Ahighly viscous slurry formed; Bprecipitate formed.               

                                      TABLE 9                                     __________________________________________________________________________    Example          26    27    28   29   30                                     __________________________________________________________________________    polyphenylene ether.sup.a                                                                      50    50    50   50   50                                     polyamide 6,6.sup.b                                                                            50    50    50   50   50                                     citric acid-1-hydrate                                                                          0.7   --    --   --   --                                     N--phenyl citric acid amide                                                                    --    0.85  --   --   --                                     N--dodecyl citric acid amide                                                                   --    --    1.2  --   --                                     N,N'--didodecyl citric acid amide                                                              --    --    --   1.84 --                                     N,N'--diethyl citric acid amide                                                                --    --    --   --   0.825                                  N,N'--dipropyl citric acid amide.sup.c                                                         --    --    --   --   --                                     Unnotched Izod ft.lb./in.                                                                      >23.4 >23.4 6.74 4.12 >23.4                                  Notched Izod ft.lb./in.                                                                        1.09  .94   .64  .67  .81                                    Tensile Yield Strength psi                                                                     11063 11165 8845 7685 10875                                  Tensile Elongation, %                                                                          23    8.5   5    4.5  10                                     __________________________________________________________________________     .sup.a & b See footnotes a & b, Table 3                                       .sup.c this acid amide was not tested                                    

                  TABLE 10                                                        ______________________________________                                        Example         H        31        32                                         ______________________________________                                        polyphenylene ether.sup.a                                                                     50       50        50                                         polyamide 6,6.sup.b                                                                           50       50        50                                         malic acid      --       0.5       --                                         N--dodecyl malic acid amide                                                                   --       --        0.5                                        Unnotched Izod, ft.lb./in.                                                                    11.05    16.57     7.06                                       Notched Izod, ft.lb./in.                                                                      .75      .94       .70                                        Tensile Yield Strength psi                                                                    8076     10657     8642                                       Tensile Elongation %                                                                          7.75     19.5      8.0                                        ______________________________________                                         .sup.a&b see Table 9                                                     

EXAMPLES 33-45

Two series of compositions were prepared in order to further demonstratethe breadth of the present invention. In these examples, variouspolyamides were evaluated alone and in combination with an additionalmodifier resin.

The specific formulations and the physical properties of thesecompositions were as shown in Table 11 and 12.

                  TABLE 11                                                        ______________________________________                                        Example      I      33     J    34     K    35                                ______________________________________                                        polyphenylene ether.sup.a                                                                  50     50     49   49     50   50                                polyamide 6.sup.b                                                                          50     50     41   41     --   --                                polyamide 12.sup.c                                                                         --     --     --   --     50   50                                citric acid (anhydrous)                                                                    --     0.5    --   0.5    --   0.5                               SEBS.sup.d   --     --     10   10     --   --                                Unnotched izod                                                                             2.7    5.9    7.0  >38.0  3.7  4.3                               impact strength                                                               (ft.-lb./in.)                                                                 Tensile Elongation %                                                                       --     --     4.1  37.0   --   --                                ______________________________________                                         .sup.a See footnote a Table 2                                                 .sup.b from Nylon Corporation of America                                      .sup.c from Hules                                                             .sup.d Styrene hydrogenated butadiene styrene triblock copolymer from         Shell                                                                    

                                      TABLE 12                                    __________________________________________________________________________                                     Notched                                                                       Izod Tensile                                 Example                                                                            Polyamide  Amount                                                                             PPE.sup.a                                                                         CAH.sup.b                                                                         SEBS.sup.c                                                                        ft.lb./in.                                                                         Elongation %                            __________________________________________________________________________    L    polyamide 6,12                                                                           45   45  --  10  0.6  6                                       36   polyamide 6,12                                                                           45   45  0.7 10  2.5  30                                      M    polyamide 6/poly-                                                                        45   45  --  10  1.2  10                                      37   amide 6,6 copolymer                                                                      45   45  0.7 10  4.1  30                                      N    polyamide 12                                                                             45   45  --  10  0.3  4                                       38   polyamide 12                                                                             45   45  0.6 10  0.9  14                                      O    polyamide 6                                                                              45   45  --  10  0.3  4                                       39   polyamide 6                                                                              45   45  0.6 10  2.4  30                                      P    polyamide 6,6                                                                            45   45  --  10  0.6  5                                       40   polyamide 6,6                                                                            45   45  0.6 10  3.1  38                                      Q    polyamide 6,6                                                                            67.5 22.5                                                                              --  10  0.8  22                                      41   polyamide 6,6                                                                            67.5 22.5                                                                              0.5 10  2.2  32                                      R    polyamide 4,6                                                                            45   45  --  10  0.6  4                                       42   polyamide 4,6                                                                            45   45  0.6 10  4.5  43                                      S    polyamide 4,6                                                                            50   50  --  --  0.5  3                                       43   polyamide 4,6                                                                            50   50  0.6 --  1.0  20                                      T    polyamide 4,6                                                                            41   49  --  10  0.3  2                                       44   polyamide 4,6                                                                            41   49  0.5 10  4.0  24                                      U    polyamide 6,I                                                                            41   49  --  10  0.5  4                                       45   polyamide 6,I                                                                            41   49  0.6 10  4.1  12                                      __________________________________________________________________________     .sup.a see footnote a Table 1                                                 .sup.b citric acid1-hydrate                                                   .sup.c Styrenehydrogenated butadienestyrene block copolymers             

EXAMPLES 46-67

A series of examples were prepared in order to further demonstrate thebreadth of the present invention as claimed. In this series of examples,various modifier resins known in the art to modify polyamides orpolyphenylene ethers for improved physical properties, especially impactstrength, and/or processability were demonstrated. The various modifierresins employed in these examples were as follows:

Surlyn 9910 and 1706--ionomer resins from E. I. duPont

Primacor 3440--ethylene-comonomer acid (heat stable EAA) from DowChemical

IM 7200--ethylene-propylene rubber/ethylene-propylene-diene monomerrubber from Uniroyal

IM 7565--ethylene-propylene-diene monomer rubber/high densitypolyethylene from Uniroyal

LDPE--low density polyethylene from U.S. Industrial Chemicals

Stereon--styrene butadiene copolymer from Firestone

Paracril--butadiene acrylonitrile copolymer from Uniroyal

HIPS--high impact polystyrene from American Hoechst

EPRgAA--acrylic acid grafted ethylene propylene rubber from Reichold

PEgMA--maleic anhydride grafted polyethylene made in accordance withSwiger et al. U.S. Pat. No. 4,147,740 having 0.75 wt. percent anhydride.

CXA E136--modified ethylene vinyl acetate from E. I. duPont

EPDMgGMA--glycidyl methacrylate grafted EPDM rubber from CopolymersRubber and Chemical Corp.

The specific compositions of each example and the physical propertiesthereof were as shown in Table 13.

                                      TABLE 13                                    __________________________________________________________________________                                   Notched                                             Modifier                  Izod Tensile                                   Example                                                                            Resin   Amt.                                                                             PPE.sup.a                                                                         PA6,6.sup.b                                                                       SEBS.sup.c                                                                        CA.sup.d                                                                         ft.lb./in.                                                                         Elongation %                              __________________________________________________________________________    46   Surlyn 1706                                                                           5  49  41  5   0.6                                                                              0.7  29                                        47   Surlyn 9910                                                                           5  49  41  5   0.5                                                                              2.1  22                                        48   Primacor 3440                                                                         5  49  41  5   0.5                                                                              1.6  19                                        49   Primacor 3440                                                                         10 36  54  10  0.5                                                                              1.1  15                                        50   IM 7200 10 49  41  --  0.5                                                                              1.0  16                                        51   IM 7565 10 49  41  --  0.5                                                                              2.0  22                                        52   LDPE    10 49  41  --  0.5                                                                              1.5  14                                        V    Stereon 10 49  41  --  -- 0.2  4                                         53   Stereon 10 49  41  --  0.5                                                                              1.9  46                                        54   Paracril                                                                              10 49  41  --  0.5                                                                              0.8  15                                        55   HIPS    9  42  40  9   0.5                                                                              2.0  22                                        56   HIPS    10 49  41  --  0.5                                                                              0.8  14                                        57   HIPS    15 44  41  --  0.5                                                                              0.8  9                                         W    HIPS    20 40  40  --  -- 4.2  2.3                                       58   HIPS    20 40  40  --  0.5                                                                              8.6  3.4                                       59   EPRgAA  7  49  41  10  0.75                                                                             1.5  25                                        X    PEgMA   10 36  54  10  -- 0.7  9                                         60   PEgMA   10 36  54  10  0.5                                                                              4.0  41                                        61   PEgMA   5  36  54  10  0.5                                                                              4.1  44                                        62   PEgMA   5  41  49  5   0.6                                                                              2.2  33                                        63   PEgMA   10 41  49  5   0.6                                                                              1.1  27                                        64   PEgMA   10 60  40  5   0.6                                                                              3.5  36                                        65   CXA E136                                                                              10 36  54  10  0.5                                                                              2.6  38                                        Y    EPDMgGMA                                                                              10 45  45  --  -- 0.7  4                                         66   EPDMgGMA                                                                              10 45  45  --  0.7                                                                              1.4  13                                        67   EPDMgGMA                                                                              5  45  45  5   0.7                                                                              2.6  26                                        __________________________________________________________________________     .sup.a & b see footnotes a & b, Table 2                                       .sup.c see footnote d Table 7                                                 .sup.d citric acid (anhydrous)                                           

EXAMPLES 68-70

Several additional compositions were prepared demonstrating variousembodiments of the present invention. Specifically, these examplesdemonstrate filled compositions, compositions prepared with combinationsof polyamides and super tough polyamides. The specific compositions andthe properties obtained were as shown in Table 14.

Examples 69 and 70 were prepared by precompounding the polyphenyleneether with citric acid and adding the super tough polyamide and glassfiber and polyamide, respectively, through an entry port to the extruderbarrel downstream from the initial feed.

                  TABLE 14                                                        ______________________________________                                        Example        68     Z      69*    70*                                       ______________________________________                                        polyphenylene ether.sup.a                                                                    49     49     50     30                                        polyamide 6.sup.b                                                                            22.5   22.5   --     --                                        polyamide 6,6.sup.c                                                                          22.5   22.5   --     40                                        Zytel ST 801.sup.d                                                                           --     --     50     --                                        citric acid (anhydrous)                                                                      0.5    --     --     0.5                                       citric acid-1-hydrate                                                                        --     --     0.75   --                                        SEBS.sup.e     10     10     --     1                                         Glass fiber    --     --     --     30                                        Stabilizer.sup.f                                                                             --     --     --     0.3                                       Notched Izod ft.lb./in.                                                                      3.5    0.2    3.75   1.7                                       Tensile Elongation, %                                                                        31     2      35.5   7.1                                       Falling Dart ft.lb.                                                                          --     --     31.7   --                                        Tensile Yield Strength psi                                                                   --     --     8076   21885                                     ______________________________________                                         .sup.a see footnote a Table 2                                                 .sup.b&c polyamides from duPont                                               .sup.d super tough, modified polyamide from duPont                            .sup.e see footnote c Table 2                                                 .sup.f stabilizer package containing hindered phenol antioxidant and          potassium and cuprous salts as heat stabilizers                               *Prepared by precompounding (see text)                                   

EXAMPLES 71-79

Various polyphenylene ether-polyamide compositions were prepared inaccordance with the improved process of the present invention.Specifically, examples within and outside the scope of the presentinvention were prepared by directly compounding all of the ingredients.Examples within the scope of the improved process of the presentinvention were prepared by precompounding the polycarboxylic acid, aloneor in combination with an amine and/or modifier resin, and subsequentlycompounded with the polyamide. The specific formulations and theproperties obtained with each are presented in Table 1.

Table 15 embodies various compositions within and beyond the scope ofthe present invention wherein malic acid comprises the polycarboxylicacid component. Comparative Example AA and Examples 71 and 72demonstrates that while a high level of dibutylamine with malic acidreduces impact strength in the compatibilized composition the samecomposition wherein the malic acid and dibutylamine and polyphenyleneether are precompounded surprisingly enhances impact strength as well aselongation and tensile yield strength. Example 73 demonstratesprecompounding of the polycarboxylic acid amine stabilizer andstyrene-butadiene-styrene triblock copolymer with the polyphenyleneether before blending with polyamide.

Similarly, Table 16 demonstrates once again the utility and theimprovement in precompounding citric acid alone or in combination withthe modifier resin or modifer resin combination prior to compoundingwith the polyamide. The improvement is made clear by comparision ofComparative Examples CC with Examples 74 and 75 as well as comparison ofExamples 77 through 79. In examples 75 and 76 the precompoundcompositions were fed into the extruder as ground particles or ungroundgranules, respectively.

                  TABLE 15                                                        ______________________________________                                        Example          AA     71     72   BB   73                                   ______________________________________                                        polyphenylene ether.sup.a                                                                      50     50     --   45   --                                   polyamide 6,6.sup.b                                                                            --     --     --   45   41                                   polyamide 6,6.sup.c                                                                            50     50     50   --   --                                   d,1-malic acid   --     1      --   --   --                                   dibutylamine     --     1      --   --   --                                   SBS.sup.d        --     --     --   10   --                                   precompound A.sup.e                                                                            --     --     51   --   --                                   precompound B.sup.f                                                                            --     --     --   --   61                                   TiO.sub.2        --     --     --   --   5                                    Notched Izod ft.lb./in.                                                                        .64    .58    .88  1.09 2.4                                  Falling Dart ft.lb.                                                                            --     --     --   14   36.9                                 Tensile Yield Strength × 10.sup.8 psi                                                    10.6   10.2   11.0 7.5  9.7                                  Tensile Elongation %                                                                           6.5    6.0    23.5 9.2  16.5                                 ______________________________________                                         .sup.a,b,c see footnote a,b,c, Table 3                                        .sup.d see footnote c Table 4                                                 .sup.e precompounded composition of 100 pts. polyphenylene ether; 2 pts.      d,1malic acid; 1 pt. dibutylamine                                             .sup.f precompounded composition of 49 pts. polyphenylene ether; 10 pts.      styrenebutadiene-styrene triblock copolymer; 1 pt. dibutylamine and 1 pt.     d,1malic acid                                                            

                                      TABLE 16                                    __________________________________________________________________________    Example      CC   74   75   76   77   78   79                                 __________________________________________________________________________    polyphenylene ether.sup.a                                                                  50   49   24.5 24.5 9.5  --   39                                 polyamide 6,6.sup.b                                                                        50   41   41   41   41   41   41                                 citiric acid-1-hydrate                                                                     --   0.7  --   --   --   --   0.7                                SBS.sup.c    --   10   10   10   10   --   10                                 HIPS.sup.d   --   --   --   --   --   --   10                                 precompound C.sup.e                                                                        --   --   24.5*                                                                              24.5**                                                                             --   --   --                                 precompound D.sup.f                                                                        --   --   --   --   39.5 --   --                                 precompound E.sup.g                                                                        --   --   --   --   --   61   --                                 stabilizer   --   --   --   --   --   --   0.3                                Notched Izod, ft.lb./in.                                                                   .69  2.9  4.5  3.4  4.2  3.4  .56                                Falling Dart ft.lb.                                                                        --   100  145  155  144  59.7 --                                 Tensile Yield Strength psi                                                                 7815 8395 8743 7641 8511 9367 8134                               Tensile Elongation %                                                                       5.5  78   45   74   39   24   11                                 __________________________________________________________________________     .sup.a,b,c see respective footnotes Table 4                                   .sup.d high impact polystyrene (rubber modified polystyrene)                  .sup.e precompound composition composed of 100 pts. polyphenylene ether,      pt. citric acid1-hydrate and 1 pt. DPK (liquid phosphate)                     .sup.f precompound composition composed of 75 pts. polyphenylene ether, 2     pts. HIPS, and 1 pt. citric acid1-hydrate                                     .sup.g precompound composition composed of 37 pts. polyphenylene ether, 1     pts. HIPS, 10 pts. SBS and 1 pt. citric acid1-hydrate                         *ground                                                                       **granules                                                               

Obviously, other modifications and variations of the present inventionare possible in light of the above teachings. It is therefore to beunderstood that changes may be made in the particular embodiments of theinvention described which are within the full intended scope of theinvention so defined by the appended claims.

We claim:
 1. An improved process for the preparation of polyphenyleneether-polyamide compositions wherein the improvement comprisesprecompounding from about 0.05 to about 4% by weight, based on the totalcomposition, of one or more aliphatic polycarboxylic acid represented bythe formula:

    (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s

or derivatives thereof wherein R is a linear or branched chain,saturated aliphatic hydrocarbon of from 2 to 20 carbon atoms; R^(I) isselected from the group consisting of hydrogen or an alkyl, aryl, acylor carbonyl dioxy group of from 1 to 10 carbon atoms; each R^(II) isindependently selected from the group consisting of hydrogen or an alkylor aryl group of from 1 to 20 carbon atoms; each R^(III) and R^(IV) isindependently selected from the group consisting of hydrogen or an alkylor aryl group of from 1 to 10 carbon atoms; m is equal to 1 and (n+s) isgreater than or equal to 2, and n and s are each greater than or equalto 0; and wherein (OR^(I)) is alpha or beta to a carbonyl group and atleast 2 carbonyl groups are separated by 2 to 6 carbon atoms, with thepolyphenylene ether and a modifier resin prior to compounding with thepolyamide in order to enhance the impact strength of the finalcomposition; said modifier resin having been derived from vinyl aromaticmonomers, the blending ratio of polyphenylene ether to polyamide beingfrom 5 to 95 percent by weight of the former to 95 to 5 percent byweight of the latter.
 2. The process of claim 1 wherein thepolycarboxylic acid is represented by the formula:

    (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s

or derivative thereof wherein R is a linear or branched chain, saturatedaliphatic hydrocarbon of from 2 to 10 carbon atoms; R^(I) is selectedfrom the group consisting of hydrogen or an alkyl, aryl, acyl orcarbonyl dioxy group of from 1 to 6 carbon atoms; each R^(II) isindependently selected from the group consisting of hydrogen or an alkylor aryl group of from 1 to 10 carbon atoms; each R^(III) and R^(IV) isindependently selected from the group consisting essentially of hydrogenor an alkyl or aryl group of from 1 to 6 carbon atoms; m is equal to 1and (n+s) is equal to 2 or 3, and n and s are each greater than or equalto 0 and wherein (OR^(I)) is alpha to the carbonyl group.
 3. The processof claim 1 wherein the polycarboxylic acid is represented by theformula:

    (R.sup.I O).sub.m R(COOR.sup.II).sub.n

or derivative thereof wherein R is a linear or branched saturatedaliphatic hydrocarbon of 2 to 10 carbon atoms, R^(I) is selected fromthe group consisting of hydrogen or an alkyl, acyl or carbonyldioxygroup of from 1 to 6 carbon atoms, R^(II) is selected from the groupconsisting of hydrogen or an alkyl group of from 1 to 20 carbon atoms; mis equal to 1 and n is equal to 2 or 3 and wherein (OR^(I)) is alpha tothe carbonyl group.
 4. The process of claim 1 wherein the polycarboxylicacid is selected from the group consisting essentially of citric acid,malic acid and salts thereof.
 5. The process of claim 1 wherein theamount of polycarboxylic acid employed is from about 0.1 to about 2% byweight based on the weight of the total composition.
 6. The process ofclaim 1 wherein the ratio of polyphenylene ether to polyamide is from 30to 70% by weight of the former to 70 to 30% by weight of the latter. 7.The process of claim 1 wherein the polyphenylene ether is a homoplymeror a copolymer having units with the repeating structural formula:##STR3## wherein the oxygen ether atom of one unit is connected to thebenzene nucleus of the next joining unit, and n is a positive integerand is at least 50, and each Q is independently a monovalent substituentselected from a group consisting of hydrogen, halogen, hydrocarbon andhydrocarbonoxy groups free of a tertiary alpha-carbon atom andhalohydrocarbon and halohydrocarbonoxy groups free of a tertiaryalpha-carbon atom and having at least 2 carbon atoms between the halogenatom and the phenyl nucleus.
 8. The process of claim 1 wherein thepolyphenylene ether is poly(2,6 dimethyl-1,4-phenylene)ether.
 9. Theprocess of claim 1 wherein the polyamide is selected from the groupconsisting of polyamide 6; polyamide 6,6; polyamide 12 and polyamide6/10.
 10. The process of claim 1 wherein the polyamide is polyamide 6/6.11. The process of claim 1 which further comprises admixing therewith upto 3% by weight of a primary or secondary amine.
 12. The process ofclaim 11 wherein the amine is precompounded with the polyphenylene etherand the polycarboxylic acid.
 13. The process of claim 11 wherein theamine is prereacted with the polycarboxylic acid prior toprecompounding.
 14. An improved process for the preparation ofpolyphenylene ether-polyamide compositions wherein the improvementcomprises precompounding one or more aliphatic polycarboxylic acidrepresented by the formula:

    (R.sup.I O).sub.m R(COOR.sup.II).sub.n (CONR.sup.III R.sup.IV).sub.s

or derivatives thereof wherein R is a linear of branched chain,saturated aliphatic hydrocarbon of from 2 to 20 carbon atoms; R^(I) isselected from the group consisting of hydrogen or an alkyl, aryl, acylor carbonyl dioxy group of from 1 to 10 carbon atoms; each R^(II) isindependently selected from the group consisting of hydrogen or an alkylor aryl group of from 1 to 20 carbon atoms; each R^(III) and R^(IV) isindependently selected from the group consisting of hydrogen or an alkylor aryl group of from 1 to 10 carbon atoms; m is equal to 1 and (n+s) isgreater than or equal to 2, and n and s are each greater than or equalto 0; and wherein (OR^(I)) is alpha or beta to a carbonyl group and atleast 2 carbonyl groups are separated by 2 to 6 carbon atoms in anamount sufficient to enhance the impact strength of the polyphenyleneether-polyamide composition, with the polyphenylene ether and a modifierresin prior to compounding with the polyamide, said modifier resinhaving been derived from vinyl aromatic monomers, the blending ratio ofpolyphenylene ether to polyamide being from 5 to 95 percent by weight ofthe former to 95 to 5 percent by weight of the latter.
 15. A process forthe preparation of polyphenylene ether-polyamide compositions, saidcomposition being derived from citric acid, a polyphenylene ether, amodifier resin and a polyamide, said process comprising precompoundingsaid citric acid with said polyphenylene ether and said modifier resinprior to compounding with said polyamide, said modifier resin beingselected from the group consisting of polymer resins derived from vinylaromatic monomers, the blending ratio of polyphenylene ether topolyamide being from 5 to 95 percent by weight of the former to 95 to 5percent by weight of the latter.
 16. The process of claim 15, whereinsaid polyamide is polyamide 6,6.
 17. The process of claim 15, whereinsaid polyphenylene ether is poly(2,6 dimethyl-1,4-phenylene)ether. 18.The process of claim 15 wherein said modifier resin is selected from thegroup consisting ofpolystyrene-polybutadiene; polystyrene-polyisoprene;poly(alpha-methylstyrene)-polybutadiene;polystyrene-polybutadiene-polystyrene;polystyrene-polyisoprene-polystyrene;poly(alpha-methylstyrene)-polybutadiene-poly-(alpha-methylstyrene); andpoly(alpha-methylstyrene)-polyisoprene-poly-(alpha-methystyrene).
 19. Aprocess for the preparation of polyphenylene ether-polyamidecomposition, said composition being derived from citric acid, apolyphenylene ether, a modifier resin and a polyamide, said processcomprising precompounding said citric acid with said polyphenylene etherand said modifier resin prior to compounding with said polyamide, saidpolyphenylene ether being poly(2,6 dimethyl-1,4-phenylene)-ether, saidmodifier resin being polystyrene-polybutadiene-polystyrene triblockcopolymer, said polyamide being polyamide 6,6, the blending ratio ofpolyphenylene ether to polyamide being from 5 to 95 percent by weight ofthe former to 95 to 5 percent by weight of the latter.
 20. A process forthe preparation of polyphenylene ether-polyamide composition, saidcomposition being derived from citric acid, a polyphenylene ether, amodifier resin and a polyamide, said process comprising precompoundingsaid citric acid with said polyphenylene ether and said modifier resinprior to compounding with said polyamide, said polyphenylene ether beingpoly(2,6 dimethyl-1,4-phenylene)ether, said modifier resin beingpolystyrene-polybutadiene-polystyrene triblock copolymer, said polyamidebeing polyamide 6,6, wherein said polyphenylene ether is present at alevel of about 45 percent by weight of said composition, said polyamideis present at a level of about 45 percent by weight of said composition,and said citric acid is present at a level of about 0.7 percent byweight of said composition.
 21. A process for the preparation of acomposition derived from melt blending polyphenylene ether resin,polyamide resin, citric acid and a modifier resin derived from vinylaromatic monomers, the blending ratio of polyphenylene ether topolyamide being 5 to 95 percent by weight of the former to 95 to 5percent by weight of the latter, the citric acid being present at alevel of from 0.05 to 4 percent by weight based on the totalcomposition, said modifier resin being present at a level of from 5 to50 parts by weight based on 100 parts by weight of the combined weightof polyphenylene ether and polyamide, said process comprising:(a)precompounding the citric acid with polyphenylene ether; (b) compoundingpolyamide with the precompounded citric acid/polyphenylene ether. 22.The process of claim 21 wherein said citric acid is a citric acid ester.23. The process of claim 21 wherein said modifier resin is astyrene-butadiene-styrene triblock copolymer.
 24. The process of claim21 wherein the blending ratio of polyphenylene ether to polyamide is 30to 70 percent by weight of the former to 70 to 30 percent by weight ofthe latter.